High speed circuit breaker with shuttle armature



H. FEHLING March 6, 1962 HIGH SPEED CIRCUIT BREAKER WITH SHUTTLE ARMATURE 5 Sheets-Sheec 3 Filed Aug. 21, 1959 March 6, 1962 H. FEHLING 3,024,330

HIGH SPEED CIRCUIT BREAKER WITH SHUTTLE ARMATURE Filed Aug. 21, 1959 3 Sheets-Sheet 2 i f Fig.2

HE/NZ FEHL/NG By m A/fomgys H. FEHLING March 6, 1962 HIGH SPEED CIRCUIT BREAKER WITH SHUTTLE ARMATURE 5 Sheets-Sheet 3 Filed Aug. 21, 1959 Inventor? HE/NZ FEHL/NG by m Affomg/s United States Patent Oihce 3,024,330 Patented Mar. 6, 1962 3,024,330 HIGH SPEED CIRCUIT BREAKER WITH SHUTTLE ARMATURE Heinz Fehling, Neumunster, Germany, assignor to Licentia Patent-Verwaitungs-G.m.b.H., Frankfurt am Main, Germany Filed Aug. 21, 1959, Ser. No. 835,251 Claims priority, application Germany Aug. 22, 1958 Claims. (Cl. 200-94) The present invention relates to circuit breakers. More in particular, the present invention relates to high-speed circuit breakers with a shuttle armature, particularly for direct current installations.

It is known in the art to provide high-speed circuit breakers having a magnet system for tripping the switch at the occurrence of overload or return currents and which magnet system comprises a holding magnet, a separating magnet and, disposed between those two magnets a shuttle armature and a contact system having a main contact and a blow-out contact. Upon opening these contacts an electric arc is produced which is driven into an arc extinction chamber by magnetic blow-out means.

These known high-speed circuit breakers suffer from considerable disadvantages. An arc extinction chamber having comparatively great dimension is required for quickly extinguishing the electric arc, particularly the arc produced with elevated direct voltages, e.g. in the order of 3,000 volts. Consequently, the known high-speed circuit breakers are comparatively big and cumbersome and require considerable space. This is particularly disadvantageous where the high-speed circuit breaker is to be used on direct current impelled vehicles such as, for example, railroad locomotives.

With the foregoing in mind it is the object of the present invention to provide a high-speed circuit breaker with a shuttle armature particularly suitable for direct current systems using elevated direct voltages which requires very little space and, at the same time, guarantees a quick and safe circuit breaking operation even in the presence of high direct voltages.

This object is achieved by the high-speed circuit breaker of the present invention which is of the type comprising a shuttling armature, a plurality of series connected contact separating points and at least two identical magnet circuit systems, each comprising a holding magnet and a separating magnet. According to the present invention this high-speed circuit breaker has the magnetic circuit systems located juxtaposed in one plane, with the magnetic flux of both systems actuating simultaneously the shuttle armature and each having a contact separating point comprising a moveable contact which is at least partly surrounded by the separating magnet. Each magnetic circuit system has a trip coil through which there flows the main current. The trip coils are series connected through the contact separating points and are used simultaneously as are extinction coils. A separate arc extinction chamber is associated with each of the contact separating points which are small since the arc voltage is distributed to the several contact separating points. The moveable contacts are constructed as contact levers in a manner known per se and are insulated from each other. They are mounted on a common shaft disposed substantially in the middle between the two contact levers, and they can be singly rotated about this shaft and are also singly spring actuated. The series connected contact separating points can be simultaneously opened by means of a trip lever having several arms and coupled with all contact levers, and which is displaced by the shuttle armature. The trip lever and the contact levers are mounted on a common shaft, but can be individually rotated thereabout.

The invention will be more fully appreciated upon the description of the accompanying drawings, wherein:

FIGURE 1 is a schematic view of the magnetic circuit system with the separating points in the high-speed circuit breaker of the invention;

FIGURE 2 is a schematic view of the magnetic systems of FIGURE 1 illustrating the magnetic blow-out effect;

FIGURE 2a is a diagram illustrating the effect of the magnetic blow-out with reference to the left-hand magnetic circuit systems of FIGURES l and 2;

FIGURE 2b is a diagram illustrating the effect of the magnetic blow-out with reference to the right-hand magnetic circuit systems of FIGURES 1 and 2;

FIGURE 3 is a perspective view of the moveable contact system and the trip lever in the high-speed circuit breaker of the invention;

FIGURE 4 is a perspective view of the shuttle armature in the circuit breaker of the invention;

FIGURE 5 is a lateral view of the circuit breaker of the invention, the frame work portions and the arc extinction chambers having been omitted for the sake of clarity.

Referring now to the drawings more in detail and turning first to FIGURE 1, the high-speed circuit breaker of the present invention comprises two separately disposed but cooperating magnetic circuit systems A and B. The two magnetic circuit systems are closely juxtaposed on either side of the thin separating insulating wall 8, and are located in one plane. Each of the two systems A and B comprises a separating magnet 1 and 1a, respectively. Opposite to the separating magnets 1 and 1a, there is disposed a pair of shunt-connected, holding magnets 2, 2a tending to retain the shuttle armature 4 in position with the free pole-surfaces 3 and 3a.

The shuttle armature 4 is composed of a pair of symmetrically disposed angle pieces 5, 5a which are rigidly connected with each other by means of plates 6, 6a composed of a tough, non-magnetic, insulating material such as, for example, plastics. (See FIGURE 4.) The shuttle armature 4 is adapted to slide on the guide member 7, which latter is also composed of insulating material. When gliding along guide member 7 after having overcome the retaining force of holding magnets 2, 2a and having detached from the pole surfaces 3, 3a of the latter, the shuttle armature 4 traverses the gap designated with A.

Returning now to the above-mentioned separating magnets 1, In, there are further provided, wound about the latter, two trip coils 9, 9a, connected in series. The trip coils 9, 9a are connected with the moveable contact levers 12, 12a, via flexible connecting straps 13, 13a. The moveable contact levers are at least partly surrounded by the iron of separating magnets 1, 1a. Opposite to the moveable contacts 12, 12a there are disposed fixed contacts 14, 14a; the contact separating points 10 and 10a are series connected with the trip coils 9, 9a. The trip coils are simultaneously used for building up the magnetic blow-out field.

The moveable contact levers 12, 12a are rotatably mounted on a shaft 30 (see FIGURE 3). The contact levers 12, 12a are made resilient by contact pressure spring 28 (see FIGURE 5). The shaft 30 further bears a six-armed trip lever 16 singly rotatably about shaft 30 and having a pair of picker arms 15, a pair of catch arms 17 and a pair of fork-shaped lifting arms 19. The shaft 30 also bears a pair of lever arms 18, 18a, extending substantially oppositely to contact levers 12, 12a. The lever arms have projecting portions 29 extending towards the six-armed trip lever 16, and screw bolts 27 allowing for a displacement of levers 18, 18a, 12, 12a relative to trip lever 16. A locking system is associated with the elements on shaft 30, and comprises two-armed locking levers 20 and 22 rotatably mounted on shaft 31. Locking lever 20 has a stud 20a projecting into the range of fork-shaped lever 19, whereas locking lever 22 is adapted to engage a stop lever 23, which latter is connected to lever 18 via levers 33, 34. Locking lever 22 is also connected with a cam 32, which in turn is connected with a pair of return springs 21, the other end of which are connected with contact levers 12, 12a.

The blow-out iron 11 is shown in FIGURE 5.

FIGURES 2, 2a and 2b illustrate the magnetic blowout effect. FIGURES 2a and 2b illustrating in a spatial vector diagram the interrelation between current I, the blow-out field Hg and the force K resulting therefrom, for the left-hand and the right-hand magnet circuit system shown in FIGURE 2, respectively.

Turning now to the operation of the circuit breaker, the current I flows from the fixed contact 14a over the moveable contact 12a, flexible connection strap 13a, coil 9a, coil 9, flexible connection strap 13 and moveable contact 12 to the fixed contact 14. The current flow through coils 9 and 2a produces in the two magnet circuit systems flux In, and I respectively. A partial flux I and respectively, enters the comparatively weaker holding magnets 2, 2a and tends to keep the shuttle armature 4 pressed against pole surfaces 3 and 3a of the holding magnets 2 and 2a, as long as normal operating conditions prevail. As soon as an overload or return current is produced the flux I becomes greater than flux so that the shuttle armature is displaced away from the pole surfaces 3, 3a of holding magnets 2, 2a. The current increase needed for producing this effect is determined by the air gap A. The armature 4 then hits against the picker arms 15 of the trip lever 16. The catch arms "17 of trip lever 16 then open the contact levers 12, 12a, separating them from fixed contacts 14, 14a. Both contacts 12 and 12a are opened simultaneously, suddenly and with great speed. Simultaneously with the aforementioned operation, the fork-shaped lifting arms 19 lift the two-armed locking lever 20 to unlock the contact system.

The pair of return springs 21 nitely into the opened position. The pair of springs 21 also moves the locking system 20, 22 into the position necessary for circuit making, after the locking lever 22 has been released by the stop :lever 23 actuated by levers 18, 18a.

The circuit breaker of the invention responds to the same degree in both current directions. It is, however, also possible to so devise the circuit breaker that it responds at a predetermined ratio of forward and return current. This can be done, for example, by providing a pair of series connected short-circuited additional coils 24 and 24a wound about the shunt-connected holding magnets 2 and 2a. Thereby the circuit breaker has become sensitive to current increase. If furthermore a direct current valve or rectifier is connected in series with the short-circuited additional coil a static release is obtained at the predetermined overload current for current direction whereas for the other current direction the release is di/dt sensitive.

The sensitivity to a current increase can be further enhanced by connecting an auxiliary current source 2a: to the additional coils 24 and 24a. If now a rectifier 25 is connected with the additional coils 24 and 24a, and thereby the induction of the coil is neutralized in one current direction, then the release of the circuit breaker is made highly di/dt sensitive in one current direction whereas it is neutral in the other current direction.

The high speed circuit breaker of the present invention offers considerable advantages over the art. The circuit breaker requires comparatively small space and guarantees a fast and safe circuit breaking effect even in the presence of high direct voltages, for example in the order of 3000 volts and more.

It is a further advantage that the dynamic forces are neutralized by the iron sheet packages of the separating magnets. The blow-out fields are positioned in the dimoves both levers defirection of the desired course of the electric art. Furthermore, since each moveable contact lever is singly resiliently disposed an equal and satisfactory contact pressure is obtained even where the various contact points have been unevenly burnt away.

it will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall Within the scope of the appended claims.

What is claimed is:

l. A high-speed circuit breaker comprising means defining a pair of similar magnetic circuits with each magnetic circuit comprising a holding magnet and a separating magnet, said pair of magnetic circuits being positioned side by side in the same plane, a first and a second fixed contact, a first and a second contact capable of respectively engaging said fixed contacts for contact making, said contacts being respectively associated with said magnetic circuits and being partially enclosed by the separating magnet of the respective magnetic circuit so that the magnetic flux partially penetrates the contact breaking point of the associated contacts; spring means for independently pivotally supporting said movable contacts, means interconnecting in series the contact points formed by each stationary contact and its corresponding movable contact, and an armature separable from said movable contacts and simultaneously actuated by said pair of magnetic circuits and engageable with said movable contaots to simultaneously separate said movable contacts from said stationary contacts.

2. A high speed circuit breaker as claimed in claim 1 wherein said armature comprises a plurality of sections, and a plurality of non-magnetic insulated plastic material plates rigidly connecting said sections to form said armature.

3. A high speed circuit breaker comprising: means defining a pair of similar magnetic circuits with each circuit including a holding magnet and a separating magnet, said pair of magnetic circuits being positioned side by side with the respective flux defining a common plane; means for simultaneously energizing said magnetic circuits; a shaft; a first and a second contact lever arm individually mounted on said shaft for independent pivot motion thereabout; a first and a second stationary contact respectively defining contact making points with said contact levers, said contact points being respectively located in the flux path of said magnetic circuits of said separating magnets; an armature separable from said contact lever arms and simultaneously actuated by said pair of magnetic circuits, and common means engageable by said armature for moving therewith and for pivoting simultaneously said independently pivotable contact levers for contact breaking.

4. A high-speed circuit breaker as described in claim 3 said common means comprising a trip lever being pivotally mounted on said shaft, said trip lever having a plurality of arms being engageable by said armature, and coupling means connecting said trip lever with said contact levers, said trip lever opening said movable contacts upon engagement by said armature.

5. A high-speed circuit breaker as claimed in claim 4 wherein said trip lever is mounted for pivotal movement on said shaft independently of said contact levers.

6. High-speed circuit breaker as described in claim 5, a plurality of catch levers on said trip lever, and a plurality of projections on said moveable contact levers, said catch levers engaging said projections whenever said trip lever is actuated by said armature thereby coupling said trip lever with said moveable contact levers.

7. High-speed circuit breaker as described in claim 5, a plurality of catch levers on said trip lever, and a plurality of projections on said moveable contact levers, said catch levers engaging said projections whenever said trip lever is actuated by said armature thereby coupling said 5 6 trip lever with said moveable contact levers, and means 1,934,467 Hopp Nov. 7, 1933 for adjusting the relative position of said catch levers and 1,966,189 Smith July 10, 1934 said rnoveable contact levers. 2,451,543 Edell 0st. 19, 1948 2,732,443 Roth Jan. 24, 1956 References Cited in the file of this patent 5 2,770,766 Kesselring Nov. 13, 1956 UNITED STATES PATENTS FOREIGN P E T 597,855 Linton Jan. 25, 1898 543,039 Germany Mar. 1, 1930 1,657,320 Roth Jan. 24, 1928 614,587 Germany Feb. 28, 1930 

